Gharīb muṭlaq (غریب مطلق) is a Hadith with a single narrator at the start of its sanad: that is, just one Successor in the Successors' generation transmitted it.
In the faith-and-modesty example, Abu Ṣāliḥ alone transmits from Abu Hurayrah. Under this division, the single narrator in the Successors' generation illustrates gharīb muṭlaq.
It is also called fard muṭlaq (فرد مطلق).